For treating a diabetic, blood of the diabetic is extracted for measuring the glucose concentration in the blood, and the treatment, for example, is determined based on the measurement. An example of prior art lancing apparatus used for extracting blood is disclosed in JP-A-2000-231.
The disclosed lancing apparatus comprises a housing including a cylindrical member having an open front end, a lancet disposed in the housing, and an analysis component disposed in the cylindrical member. In using the lancing apparatus, while the front end of the cylindrical member is held pressed against skin of a human body, the lancet is advanced toward the front end of the cylindrical member. As a result, the tip end of the lancet sticks into the skin to cause bleeding from the skin. The analysis component is provided with a reagent. When the blood is supplied to the analysis component and then guided to the reagent, an intended reaction occurs between the glucose in the blood and the reagent. The glucose concentration in the blood can be determined based on the degree of the reaction. Therefore, the above lancing apparatus is convenient as compared with a lancing apparatus which is not provided with such an analysis component and which has the lancing function only.
In using the lancing apparatus with an analysis component, it is desirable to locate the analysis component as close as possible to the bleeding portion of the skin so that the blood can be reliably supplied to the analysis component. However, with the prior art device, the supply of blood is sometimes difficult for the following reasons.
When the front end of the cylindrical member of the lancing apparatus is pressed against the skin, the skin may bulge. The amount of such bulging varies depending on the softness of the skin and the strength of the force in pressing the cylindrical member. However, in the prior art lancing apparatus, the analysis component is fixed at a certain position in the cylindrical member. Therefore, depending on whether or not the skin bulges or how much the skin bulges, the distance between the bleeding portion of the skin and the analysis component may increase, which makes it difficult to properly supply the blood to the analysis component.
In extracting blood using such a lancing apparatus, it is preferable to generate negative pressure in the cylindrical member using a negative pressure pump. In such a case, the negative pressure promotes bleeding from the lanced portion of the skin so that the amount of lancing by the lancet into the skin can be advantageously reduced. However, when negative pressure is generated in this way, the skin bulges greatly due to the action of negative pressure. Therefore, the distance between the bleeding portion of the skin and the analysis component may further increase, which further makes it difficult to properly supply the blood to the analysis component.